1. Field of the Invention
The invention relates to a lead frame for an integrated semiconductor device, and more particularly, to a lead frame in which the occurrence of an undesirable flash coating during the molding process step in the manufacturing process is prevented by modifying the shape of the side rail of the lead frame.
2. Information Disclosure Statement
The lead frame of the prior art is, as shown in FIG. 1, formed into a structure in which each end (U, Z) of side rails 2H, 2Y, respectively, on both sides of a lead frame 1 extends beyond the cavity whereas the remaining ends X, Y of side rails, 2H, 2Y, respectively, terminate proximate the cavity with a cut which is perpendicular to the direction of the side rail.
Therefore, there is a problem in that during the molding process of the lead frame 1 for encapsulating a chip portion IA mounted at a cavity 3 of the lead frame 1, the epoxy resin mis-flows in the direction of an arrow "K" as shown in FIG. 3 through ends X,Y of the side rails 2H, 2Y of the lead frame which terminate proximate the cavity, producing a flash coating 9 in the lead surface 7 which is the surface which exists between a runner 5Y and each lead 8 of a plurality of leads 8N.
Therefore, it is an object of the present invention to provide a lead frame in which the occurrence of an undesirable flash coating during the molding process is prevented by forming side rails having an end which diagonally terminates in a point which is distally positioned relative to the cavity.
It is a further object of the present invention to provide a lead frame which is economical to produce.
The preceding objects should be construed as merely presenting a few of the more pertinent features and applications of the invention. Many other beneficial results can be obtained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to both the summary of the invention and the detailed description, below, which describe the preferred embodiment in addition to the scope of the invention defined by the claims considered in conjunction with the accompanying drawings.